The present invention provides a method and system for network certification, the method comprising: establishing a roaming group at a cloud AC, and dividing APs from one same roaming group into one same Layer 2 multicast domain, such that upon sending out a certification request by a station to a target AP, it is determined whether or not a local certification list of the target AP includes association certification information between a roaming group AP where the target AP is located and the station; if the local certification list of the target AP includes the association certification information between the roaming group AP where the target AP is located and the station, approving the certification via the station. When the cloud AC and the AP are located in different local area networks, the method for network certification reduces processes when requesting certification across public networks and increases certification efficiency, thereby achieving painless certification at a station.